ssh on port 21?

[rab]

Mark Knecht wrote:

>>
>>
>> Yes, the ports must match. If you have the daemon listening on port N,
>> you must tell the client to use port N, also. Otherwise the client will
>> try port 22 and since there's nothing listening on port 22, nothing will
>> happen.
>
>
> As Rick said, but additionally, as I indicated last evening, if you 
> are going from work to your house, and your house has a firewall or 
> router, then you need to set up port forwarding on your firewall or 
> router to point the incoming port 21 traffic (if that's what you end 
> up using) to the specific internal machine you want to talk to at 
> home. You seem to have understood that in your original question, but 
> I'm not sure any of us said exactly 'Yes', so I am. ;-)
>
> Good luck,
> Mark
>
I looked at the router firewall admin webpage. There is a public port 
and a private port for forwarding. Suppose at work I'm ssh'ing out port 
21 and I have sshd listening on port 22 (the standard port) with the 
port forwarding set for tcp 22/22. Can I leave the forwarding rule as it 
is and add a new rule that has public port 21 and prive port 22? In 
other words, can I take traffic from port 21 on my work pc and forward 
them to port 22 on my home pc behind the firewall? Do I understand this 
correctly?

If that doesn't work, can I listen for ssh traffic on both ports 21 and 
22? I know I can ssh in to my home pc on port 22 and I rather not change 
that if I can avoid it.

Rick B.